Giant 20' x 3' x 2' router build

[charlieuk]

I'm not giving in! Just wired a short length of cable (2m) straight from the csmio to the same switch and it works perfect so I ether need to some how change the wiring or the switches.

[EddyCurrent]

For limits I prefer this type, mechanical with a roller arm. I assume your Home switches are close to the control unit ?

http://www.ebay.co.uk/itm/ME-8108-Mo...algo=undefined

Also looking at some earlier photo's I don't like the look of your 'target' for the sensor. It looks like a stainless cap head screw, try a piece of flat mild steel instead or a large steel bolt head for example.

[charlieuk]

The home switches are all on the gantry the only or that could be made closer to the control box is the x home. The triggers are at the moment a stainless bolt in a alli washer I will try all steel now

[charlieuk]

just tried just a steel bolt and it still had the fault

[EddyCurrent]

just tried just a steel bolt and it still had the fault

Did it have a hole in the middle like the cap head screw or was it solid metal right across and at least the same diameter as the proximity switch ?

This is from Baumer inductive sensors catalogue.
Baumer

"Maximum cable length A large cable length is a capacitive load for the output circuit and increases the influence of interference. Length should therefore be kept as short as possible."

They don't quote a figure for max length though.

This is why I suggested using single core bits of wire just as a test over the distance, the capacitance is going to be low if they are kept well apart.

Save yourself the grief and fit mechanical switches for limits, you won't have these problems then.

[charlieuk]

It was a m10 flat head bolt. The stainless bolt works fine on the short cable

[JAZZCNC]

Save yourself the grief and fit mechanical switches for limits, you won't have these problems then.

But thats masking any issues not resolving them.! Charlies wire run isn't long, it's just longer than your average CNC machine but for industry 10-12mtr isn't long.
Mechaincal switches are OK for Limits I agree but what does he do then about Home switches.? . . Shouldn't have to put up with lesser accurecy by using mechanical switches.
I'm sure the problem lies with the fact these Cheap chinese switches obviosly don't like the longer wire run and any capacitance thats coming with it.! . . . . . That or he's got some other issue he isn't aware of yet.?

[EddyCurrent]

But thats masking any issues not resolving them.!

No, it's about finding the right product for the job, I know that mechanical switches will be unaffected over the length of cable he's using, plus I'm trying to find a solution that's cheap and easy to implement. If Charlie want's to keep going to resolve the issues that's fine, I don't have a problem with that.

Charlies wire run isn't long, it's just longer than your average CNC machine but for industry 10-12mtr isn't long.

which is why we used these connected via stanadard armoured cable, okay up to 200m according to Schneider.

http://uk.rs-online.com/web/c/automa...004,4294876081

. . .but what does he do then about Home switches.? . . Shouldn't have to put up with lesser accurecy by using mechanical switches.

No, that's why I mentioned in an earlier post about his Home switches being near to the control box, it would make sense to have the Home position at that end.

I'm sure the problem lies with the fact these Cheap chinese switches obviosly don't like the longer wire run and any capacitance thats coming with it.! . . . . . That or he's got some other issue he isn't aware of yet.?

That is the best conclusion now, but with fault finding it's best to start with the easy things first and in the case of DIY, the cheapest too, and I don't like guessing, it's far better to work through logical steps then we all know the 'correct' answer if it comes up again.

[JAZZCNC]

No, it's about finding the right product for the job, I know that mechanical switches will be unaffected over the length of cable he's using, plus I'm trying to find a solution that's cheap and easy to implement. If Charlie want's to keep going to resolve the issues that's fine, I don't have a problem with that.

Don't talk daft Man course it's masking the problem if you haven't found out why.!! Also you can't say proximity switches are the wrong product for the job of sensing it's what they are made to do for gods sake.! Only thing that could be questioned is the quality for intended application.

No, that's why I mentioned in an earlier post about his Home switches being near to the control box, it would make sense to have the Home position at that end.

That's ok for one axis what about the other Two. . ? Still got to accept lesser accurecy just to make it work M-Switch.! . . . Shouldn't and doesn't have to be that way.

That is the best conclusion now, but with fault finding it's best to start with the easy things first and in the case of DIY, the cheapest too, and I don't like guessing, it's far better to work through logical steps then we all know the 'correct' answer if it comes up again.

We started with Logical steps and eliminating obvious potential issues which don't cost money and now it's got to the point where it's time to swap components to see if fault or weak parts are the cause. Swapping out for inferior accurecy components shouldn't be even considered IMO. Esp with home switches.!!